SF: Implement FrameStats directly in FrameTimeline

Bug: 241394120
Test: builds, atest CtsUiAutomationTestCases:android.app.uiautomation.cts.UiAutomationTest#testWindowContentFrameStats$
Flag: com.android.graphics.surfaceflinger.flags.deprecate_frame_tracker
Change-Id: I3f12d504e821a6ba15a26604eb56f317c9d59a18
diff --git a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
index 47b811b..c13e444 100644
--- a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
+++ b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
@@ -378,6 +378,11 @@
     }
 }
 
+void SurfaceFrame::setDesiredPresentTime(nsecs_t desiredPresentTime) {
+    std::scoped_lock lock(mMutex);
+    mActuals.desiredPresentTime = desiredPresentTime;
+}
+
 void SurfaceFrame::setDropTime(nsecs_t dropTime) {
     std::scoped_lock lock(mMutex);
     mDropTime = dropTime;
@@ -1456,6 +1461,30 @@
             static_cast<float>(totalPresentToPresentWalls);
 }
 
+void FrameTimeline::generateFrameStats(int32_t layer, size_t count, FrameStats* outStats) const {
+    std::scoped_lock lock(mMutex);
+
+    // TODO: Include FPS calculation here
+    for (auto displayFrame : mDisplayFrames) {
+        if (!count--) {
+            break;
+        }
+
+        if (displayFrame->getActuals().presentTime <= 0) {
+            continue;
+        }
+
+        for (const auto& surfaceFrame : displayFrame->getSurfaceFrames()) {
+            if (surfaceFrame->getLayerId() == layer) {
+                outStats->actualPresentTimesNano.push_back(surfaceFrame->getActuals().presentTime);
+                outStats->desiredPresentTimesNano.push_back(
+                        surfaceFrame->getActuals().desiredPresentTime);
+                outStats->frameReadyTimesNano.push_back(surfaceFrame->getActuals().endTime);
+            }
+        }
+    }
+}
+
 std::optional<size_t> FrameTimeline::getFirstSignalFenceIndex() const {
     for (size_t i = 0; i < mPendingPresentFences.size(); i++) {
         const auto& [fence, _] = mPendingPresentFences[i];